A foreign national walks toward the departure area of Sanaa International Airport before leaving Yemen. Many Westerners have left the country amid warnings of a possible terrorist attack.

Mohammed Huwais
/ AFP/Getty Images

Originally published on August 7, 2013 2:29 pm

Almost every time the U.S. government gets wind of a potential terrorist attack, it faces a tough choice: It can quietly pursue the suspected plotters, or it can go public in the belief that public awareness can discourage or thwart the attack.

In the current episode, the Obama administration has gone public in a big way, announcing the threat, temporarily shutting more than 20 U.S. embassies and diplomatic posts from Rwanda to Bangladesh, and evacuating many embassy workers in Yemen, the country described as the main source of the threat.

"One thing I've tried to do as president is not overreact, but make sure that as much as possible the American people understand that there are genuine risks out there," President Obama told Jay Leno on The Tonight Show on Tuesday evening.

Reasons To Go Public

By announcing the threat, the U.S. could potentially buy time and perhaps force al-Qaida to delay or cancel a planned attack, because it will now suspect that an operation is much more likely to be foiled.

"You usually want to keep things quiet to protect your intelligence sources, and your chances of disrupting an attack are better if the attackers don't know you're looking for it," says Daniel Byman, a professor of security studies at Georgetown University. "But if your information is vague, you might be better going public and letting everyone know that you know something."

Based on what the government has said so far, the U.S. seems to believe something is in the works, but has not been able to uncover the details, according to Gregory Johnsen, a Yemen expert who teaches at Princeton University.

Closing so many embassies suggests the government "has a little bit of information about this, but it has very fragmentary pieces of information, and it's really scrambling right now to put together the whole puzzle," says Johnsen, author of The Last Refuge: Yemen, al-Qaeda, and America's War in Arabia.

Meanwhile, the BBC reported Wednesday that the plot in Yemen had been disrupted, and that the targets were linked to the country's oil industry. Rajeh Badi, a government spokesman in Yemen, said attacks had been planned for oil pipelines and ports where oil is exported, the BBC quoted him as saying.

The Obama administration faced the current case against the backdrop of last year's attack on a U.S. diplomatic mission and a CIA compound in Benghazi, Libya. That Sept. 11 assault left four Americans dead and brought a firestorm of criticism about a lack of preparation despite an extremely volatile security environment.

By closing embassies this time, the Obama administration is demonstrating that it does not want to risk a repeat of Benghazi.

"I don't have any criticism of the tactical choice to close the embassies in this case," says Brian Fishman, a counterterrorism researcher at the New America Foundation. "But what worries me is that it contributes to the larger trend of turning embassies into fortresses."

Reasons To Act In Secret

The downside of going public is that it alerts al-Qaida, potentially exposes intelligence sources, and prompts a flood of media reports that may reveal far more information than the government would like.

In this case, multiple reports have cited U.S. intelligence intercepts of communications sent by al-Qaida leader Ayman al-Zawahri. But now Zawahri and other al-Qaida leaders have been tipped that their communications have been compromised.

The Daily Beast reported Wednesday that the U.S. intercept came when Zawahri and more than 20 al-Qaida leaders and operatives took part in a conference call. The report cited three U.S. officials familiar with the intelligence.

Al-Qaida leaders "had assumed the conference calls, which give Zawahri the ability to manage his organization from a remote location, were secure. But leaks about the original intercepts have likely exposed the operation that allowed the U.S. intelligence community to listen in on the al-Qaida board meetings," The Daily Beast said.

The report added that the call included al-Qaida members or affiliates based in Nigeria, Pakistan, Iraq and North Africa, among other places.

This case comes amid the controversy surrounding the National Security Agency and its methods of collecting data. The recent revelations have recast the debate, at least for now, on terrorism prevention rather than privacy issues involving U.S. citizens.

"A vast amount of our information comes from signals intelligence, and based on what we know, this case shows how valuable the NSA is," says Byman, the Georgetown professor. "As far as I know, we don't have a spy who can talk to Zawahri the way the NSA can potentially monitor him."